On Thu, 10 May 2018 05:35:56 +0900,
TJ OConnor wrote:
> 
> [1  <text/plain; utf-8 (quoted-printable)>]
> Sir,
> 
> Thank you for the response. I am writing packets exactly like this and it is 
> still truncating packets that are > 62 bytes.
> 
> 
>         class SimpleSwitch13(app_manager.RyuApp):
>             OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
>             def __init__(self, *args, **kwargs):
>                 super(SimpleSwitch13, self).__init__(*args, **kwargs)
>                 self.mac_to_port = {}
>                 # Create pcaplib.Writer instance with a file object
>                 # for the PCAP file
>                 self.pcap_writer = pcaplib.Writer(open('mypcap.pcap', 'wb'))
>             ...
>             @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
>             def _packet_in_handler(self, ev):
>                 # Dump the packet data into PCAP file
>                 self.pcap_writer.write_pkt(ev.msg.data)

ryu.lib.pcaplib.Writer's default snaplen is 65535, so it's more likely
the packets are truncated on arrival of packet-ins.

Please check 7.4.1 Packet-In Message of the OpenFlow spec 1.3.5 and
referenced sections for details.

> 
> > On May 3, 2018, at 1:20 AM, TJ OConnor <tj_ocon...@me.com> wrote:
> > 
> > Hello,
> > 
> > I have an issue where RYU pcaplib.Writer() isn’t writing full packets. 
> > 
> > Ive created a RYU PCAP Writer Object as described here. 
> > https://github.com/osrg/ryu/blob/master/ryu/lib/pcaplib.py 
> > <https://github.com/osrg/ryu/blob/master/ryu/lib/pcaplib.py>
> >     self.pcap_writer = pcaplib.Writer(open('mypcap.pcap', 'wb’))
> > 
> > However, when I tcpdump the resulting pcap, it shows that the packets are 
> > all truncated at 62 bytes. 
> > I’ve adjusted the snaplen=4294967295 and the issue is still the same. 
> > 
> > Any suggestions would be greatly appreciated. 
> > 
> > tcpdump -r mypcap.pcap …
> > 
> > 23:05:39.948667 IP truncated-ip - 1 bytes missing! ubuntu.65277 > 
> > amazonaws.com.https: Flags [P.], seq 317:380, ack 253, win 4096, options 
> > [nop,nop,TS val 800045157 ecr 739067198], length 63
> > 23:05:39.995833 IP truncated-ip - 1 bytes missing! amazonaws.com.https > 
> > ubuntu.65277: Flags [P.], seq 253:316, ack 380, win 1136, options 
> > [nop,nop,TS val 739069697 ecr 800045157], length 63
> > 
> > 
> > 
> > 
> > 
> 
> [2  <text/html; utf-8 (quoted-printable)>]

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